Point defect model for passivity breakdown on hyper-duplex stainless steel 2707 in solutions containing bromide at different temperatures

Passivity breakdown on HDSS 2707 has been studied and the electrochemical data are interpreted in terms of the Point Defect Model. Pitting parameters of HDSS 2707 are determined, including the polarizability at bl/s interface, the defect annihilation rate, and the defect diffusion coefficient. The breakdown potential is demonstrated to be linearly related to log [Br-], pH, and the square root of potential scan rate (v1/2), and follows a nearnormal distribution. The critical vacancy concentration calculated from the PDM is consistent with that estimated crystallographically from the chromic barrier layer, and the dominant point defect is further confirmed by Mott-Schottky measurements.

Automated summary

Passivity breakdown on HDSS 2707 has been studied and interpreted using the Point Defect Model. Pitting parameters of HDSS 2707, such as polarizability at bl/s interface, defect annihilation rate, and defect diffusion coefficient, have been determined. The breakdown potential is shown to have linear relationships with log [Br-], pH, and the square root of potential scan rate (v1/2), following a near-normal distribution. The critical vacancy concentration calculated from the PDM aligns with crystallographic estimates from the chromic barrier layer, and the dominant point defect is confirmed through Mott-Schottky measurements.